Shell script for cross-platform compatibility in filenames

Question

I'm trying to create a shell script to run via my file manager's context menu to make certain replacements in some file names that might cause problems when transferred across different platforms (Linux, MacOS, Windows etc.).

I have so far managed the obtain the following (probably quite dirty) code with my beginner-level scripting skills, but I'm still struggling to find a way to replace these characters: ‘ ’ “ ” / (When I use these smart single and double quotes, and slash like other sed expressions, the file is deleted!).

And another problem I'm struggling is that this script fails to remove a space before the file name although it works when entered directly in terminal.

I would appreciate some help in finding a solution for this.

for filename in "${@}"; do
    NEWNAME="$(echo "$filename" | sed -e 's/:/-/g' -e "s/'//g" \
    -e 's/["|?|*]//g' -e 's/[<|>]/ /g' -e 's/\\/ /g' -e 's/\[/ /g' \
    -e 's/\]/ /g' -e 's/\s\s*/ /g' -e 's/^\s\s*//g' -e 's/\s\s*\./\./g')"
    mv "$filename" "$NEWNAME"
done

Answer 1

Just use perl-rename (found as rename on Debian and Ubuntu etc). First, for testing, let's create an awful name:

touch "   a truly “horrible”, ‘awful’"$'\n'"name     with a newline and *globs*, and even a 'single' quote or two!   .txt"

This is what that looks like:

$ ls
'   a truly “horrible”, ‘awful’'$'\n''name     with a newline and *globs*, and even a '\''single'\'' quote or two!   .txt'

Note that that there is a literal newline character, if you try to loop over this (badly), you will see:

$ for f in *; do echo "$f"; done
   a truly “horrible”, ‘awful’
name     with a newline and *globs*, and even a 'single' quote or two!   .txt

So, that name has most if not all the problems you'll be facing. Now, use rename to get rid of the bad characters:

$ rename 's/[*“”‘’\n<|>"[\]]//g; s/:/-/g; s/\s+/ /g; s/^\s*//; s/\s+\././g; '"s/'//g" *
$ ls -N
a truly horrible, awfulname with a newline and globs, and even a single quote or two!.txt

As you can see, that removed all of the bad things you were looking for (as far as I could tell since I only had your sed attempt to go on). You could fit this into your script like this:

for filename in "${@}"; do
    rename 's/[*“”‘’\n<|>"[\]]//g; 
    s/:/-/g; 
    s/\s+/ /g; 
    s/^\s*//; 
    s/\s+\././g; '"s/'//g" "$filename"
done

Explanation

The basic syntax is very similar to sed, you are using the same substitution operator. The regular expressions are:

• s/[*“”‘’\n<|>"[\]]//g; : substitute every occurrence of *, “, ”, ‘, ’, \n, <, |, >, ", [, or `] with nothing, delete them.
• s/:/-/g: substitute every occurrence of any whitespace character (basically a space, a tab or a newline) with -.
• s/\s+/ /g: substitute all occurrences of one or more consecutive whitespace characters with a single space. *s/^\s*//: remove all leading whitespace from the beginning of the file name,
• s/\s+\././g : remove all occurrences of one or more whitespace characters that come before a ..
• "s/'//g": remove all single quotes. Note how the whole command is rename '...' and then I have added "s/'//g". This is because you cannot escape a single quote within a single-quoted string, so I had to close the single-quoted string and open a new, double quoted one to deal with the ' characters.

Also, I did not bother to deal with /, since / along with \0 are the only characters that are not allowed in filenames and you simply cannot create a file name that contains a /.